Background: Upper gastrointestinal manifestations of inflammatory bowel disease (IBD) are well established, particularly in Crohn's disease (CD). Although focally enhanced gastritis (FEG) is thought to be a characteristic gastric manifestation of IBD, most studies focus predominantly on adults. This study aims to describe detailed histological features of upper gastrointestinal manifestations of IBD including FEG in pediatric patients.Design: We selected 119 consecutive pediatric patients (1-20 years old) with confirmed IBD (62 CD and 57 ulcerative colitis [UC]), who underwent both upper and lower gastrointestinal biopsies before therapy was initiated. Upper GI biopsies from age-matched healthy controls (n=66) were also evaluated. Histological review, blinded to the final diagnosis, was performed to determine the incidence of FEG and its relationship to age group and other histologic findings.Results: FEG was present in 43% of IBD patients (CD 55% vs. UC 30%, p=0.0092) and in 5% of controls. Among CD patients, the frequency of FEG was higher in younger patients (73% at age ≤10, 43% at age >10, p=0.0358) with peak in the 5-10 years age-group (80%). In addition, the presence of FEG was significantly associated with the identification of granulomas in the entire gastrointestinal tract (p=0.0006). Comparing CD patients with and without FEG, the prevalence rate of active small bowel inflammation (presence of active duodenitis or ileitis) was higher in patients with FEG (62% vs. 36%, p=0.0412). Furthermore, the total number of glands involved in FEG foci was significantly higher in UC (6.4±5.1 glands) than in CD (4.0±3.0 glands, p=0.0465). Granulocytic infiltrates were more often observed in UC (47%) than in CD (24%), but this did not reach statistical significance. Finally, in UC patients, there was no correlation between the presence of FEG and other gastrointestinal findings, including the activity of proctocolitis.Conclusions: We demonstrate that the differences in FEG between CD and UC relate not only to their frequencies, but also to their morphology and their relationship with other gastrointestinal findings. Notably, FEG is more common in younger patients. Furthermore, in pediatric CD, FEG may be an indicator of disease activity as its presence is commonly associated with small bowel disease.Category: Gastrointestinal